There is excess air in the camera housing

Do I have to remove it?

pressure x volume = constant

the volume of air in the housing (just as that in the lungs, diving jacket and the air inclusions in the diving suit) decreases as you descend under water.

The air is pressed into the camera / camcorder. As we want the pressure inside the housing to be the same as the surrounding pressure, we have to start the dive with a suitable amount of air inside the housing. The foam pads supplied with the housing are part of this air "reservoir". In the case of the U-A, U-AX and U-AXP additional air can be blown into the housing to ensure, that the maximum potential volume is being utîlised.

On the other hand, if you only want to snorkel, you might want the housing to handle relatively neutral in the water....

Tip:

If you want to snorkel or film on the beach, remove all excess air.

If you want to go diving, ensure that there is enough air depending on your planned diving depth